Although devices like Roku‘s have managed to eke out a healthy business for themselves for the past couple of years, 2010 has been the year that set-top boxes have really exploded thanks to the efforts of companies like Google with the Google TV and Apple with their similarly eponymous set-top box.

Now Asus wants a bigger piece of the pie: they’ve just expanded their O!Play media player range with the O!Play Mini, a stripped down version of the O!Play HD2. Unlike the impressively specced HD2, the Mini does not sport any USB 3.0 connectivity, which is probably okay given the standard’s slow adoption rates. Even so, though, it manages to output video at 1080p through USB 2.0 and a multimedia card reader that will read SD, MMC, Memory Stick and XD card formats.

Output is handled by an HDMI 1.3 port on the back of the device, capable of driving 7.1 SurroundSound audio in Dolby Digital AC3, DTS 2.0+, True HD and DTS-HD sound. There’s also an RCA port thrown in for good measure. File formats supported include MP4, MOV, XVID, AVI, ASF, WMV, MKV and FLAC.

The price is the most impressive thing about the O!Mini: it’ll cost you just $90.